233 research outputs found
Osteopontin regulates human glioma cell invasiveness and tumor growth in mice
Human malignant glioma cells are characterized by local invasion. In the present study, we investigated the role of osteopontin (OPN) in the invasiveness of human glioma cells isolated from grade IV tumors. We found that the expression levels of OPN in these cell lines paralleled matrix metalloproteinase-2 (MMP-2) expression and cell invasiveness potential. When U87MG glioma cells (with a high-OPN expression level) were stably transformed with specific small hairpin RNA to knock down OPN expression, MMP-2 secretion, cell invasiveness, and tumor growth in implanted brains were dramatically reduced. Conversely, forced expression of OPN in GBM-SKH glioma cells (which expressed OPN at a low level) increased MMP-2 secretion, enhanced cell invasiveness, and increased tumor growth in a rodent xenograft model. Expression of OPN was associated with increased expression of vimentin and decreased expression of glial fibrillary acidic protein. Treatment of glioma cells with 5-aza-2ā²-deoxycytidine (5-aza-dC) suppressed OPN expression in a concentration-dependent manner. Suppression of OPN expression by 5-aza-dC was associated with reductions in MMP-2 secretion, vimentin expression, cell invasion, intravasation, and tumor growth. These data suggest that OPN may play important roles in regulating cell invasion in glioma cells and that 5-aza-dC may serve as a therapeutic agent for human gliomas
Helicity-dependent cross sections for the photoproduction of pairs from nucleons
The double-polarization observable and helicity-dependent cross sections
, have been measured for the photoproduction of
pairs off quasi-free protons and neutrons at the Mainz MAMI accelerator
with the Crystal Ball/TAPS setup. A circularly polarized photon beam was
produced by bremsstrahlung from longitudinally polarized electrons and impinged
on a longitudinally polarized deuterated butanol target. The reaction products
were detected with an almost covering calorimeter. The results reveal
for the first time the helicity- and isospin-dependent structure of the reaction. They are compared to predictions from
reaction models in view of nucleon resonance contributions and also to a refit
of one model that predicted results for the proton and for the neutron target.
The comparison of the prediction and the refit demonstrate the large impact of
the new data.Comment: Submitted to Phys. Rev. Let
Gender Differences in Competitiveness and Risk Taking: Comparing Children in Colombia and Sweden
Antitumour activity of miltefosine alone and after combination with platinum complexes on MXT mouse mammary carcinoma models
Knowledge Cluster Formation in Peninsular Malaysia: The Emergence of an Epistemic Landscape
Gender-Specific Effects of Unemployment on Family Formation: A Cross-National Perspective
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